Underreamer



Dec, 30, 1924.

R. R. SMITH lUNDERmmvnzfi Filed Feb. 20, 1922 JIU Patented Dec. 30,1924.

UNITI-:D STATES 1,520,971 PATENT @imei-1.;

RICHARD It. SMITH, or ToItRANCE, CALIFORNIAAssICNoB. To UNION .TooLCoM-lPANY, or TOImANCE, CALIFORNIA, A CORPORATION or CALIFORNIA.

UVNDERREAMER.

Application filed February 2011922. serial iN'.' 533,001.l

)To all 'whomz't may concern: i Be it known that I, RICHARD R. SMITH, acitizen of the United States, vresiding at Torrance, in the county ofLos Angeles and 1 means for locking the key against displacement.

Another Objectis to movable cutter supporting key yassoclated with aspring rod and engaging 1n transverse openings .in vthe cuttersandremovable through one of said openings after lirst being moved to atilted position, means as sociated with one of the cutters preventingsuch tilting movement of the key until saidl be more fully apparent'fromthe followingk description and the -accompanyin drawings, which form apartof this `dlsclosure,

and which illustrate a preferred form of embodiment of the invention.

Of the drawings: r Fig. l is a side elevation of the lower end of anunderreamer embodying my improvements. t r V Fig. 2 is a verticalsection on line 2 2, of Fig. 1. Fig. 3 is a locking means. r

Fig.4 is a perspective view ofthe cutter supporting key. t f' Describedin general terms, the underreamer illustrated in the` drawings consistsof abody 1 having a central bore in which slides a spring rod or mandrel2 normally subjected tov an upward tension of a spring 3 which'ispositionedin aspring chamber 4 and surrounds the rod. 'lhe lower portionof the body has o posedropen slipways 5 on opposite 4sides o the rod 2in` which perspective view'of the. key

rovide with a re.

slide the lshanksjtot the. respectivefc'utters or slips-7, the sidewalls vofthecutter Shanks beingprovidedwith out-thrust bearing ribs v8'adapted to 'l engage in' corresponding grooves 9 in the side walls ofthe slipways 5.v

The inner `face ofeach shank 6 is cut away to form an inclinedshoulderlOwhich engages under the respective expanding shoulder 11` at the lower4end of the body when the i cutters 4are in collapsed'position.`

As `thus far described the construction" shownfollowsa general formv ofstructure more or less lcommon to several well known makesofunderreamers and it is` thought that specific orfurther description ofstructure or operation would be superfluous.

v The cutters or slips 7 are supported uponv the lower end of the `rod 2by afremov'able.

key 12 which loosely engages through a transverse 'slot 13 in saidrodwith its opposite ends Or tangsextending into slots 14 inv the shanksiofthejrespective slips. One i of the slots, for 'example the-righthand'slot, is of justsuiicient vertical-depthto receive the adjacent-endof the` keyand maintain substantial engagement with its edges. Themedial portion of the key12 has an 'eXtension or wing 15 which projectsy'upwardly f between the -two clutterl shankslso that `as long as the'keyis maintained in a normal position it is retained against displacement.4

At the outeil ends the upper edge of the key is included downwardly,as`at 16,-so as lto permit a tilting `ot the cutters or'slips during' theirvertical movements in the slipways incident to acollapsing or expandingof the cutters.` l

In removing the slips or cutters 7 from the body it is'lirst necessarytoremovefthe key 12y through the slotll ofone yof the'cutters and orthis'reason'said slot, as-for in-y` stance that of the le'ft hand cutter inFi ter to permit a tilting of the 'key and its removal endwise throughthe slotf'o saidi cutter shank, as' indicated in dotted lines.- Thistilting is facilitated because `I allow clearance -above and 4below theright hand tang of the key'inthe vslot'of the right' hand cutter asillustrated'in Fig.`2. It will be* understoodthat such tilting ofthe key12 for subsequent, removal, is v`necessary 'in or- -derthat theex'tensionyl5` may clearvthe upper edge of the slot 14, and it will alsobe evident that to accomplish a removal of the key 12 it will benecessary to ulldownwardly upon the spring rod 2. uch downward pull on`the sprin rod is effected by engaging a rod 17,as indicated in dottedlines in Fig. 2, into a screw threaded recess in the lower end of thespring rod, and applying suliicient pulling power vtosaid rod 17 toovercome the tension of the spring 3. The inclined edge 16 on the end ofthe key remote from the locking member facilitates this tilting of thekeys, see Fig. 1.

It has been found desirable in this type of underreamer to provide somemeans. of positively locking the key against removal so as to obviateany likelihood of the parts becoming deranged through use or wear and toprevent an accidental loss of the key, especially while the underreameris being operated in a well bore, as such accidental loss of the keywould result in a loss of both cutters.

To positively lock the key 12 in assembled position I providev allockmember20, associated with the left hand cutter in Fig. 2, said memberhaving a beaded lower edge 21 provided with a threaded recess 23, and atransverse aperture 24. This lock member is in the form ofa plateextending longij tudinally with the key, and it has a sliding fit in arecess 25 vertically-aligned and com-v municating with the slot 14 inthe cutter shank 6 and is retained in position by a rivet 26 extendingthrough the walls of said recess and throughthe aperture 24, with theupper edge of the lock member positioned below the lower edge of theadjacent end of the key 12 (see Fig. 2.) When assembled in thisrelation, the surface of the upper edge of the lock member 20 extendslongitudinallyunder the key, engages it, and prevents a tilting of thekey 12 so that the key is positivel locked against removal.

A ter first removing therivet 26 the lock member 20 may be removed bythe use of any suitable form of tool screwed into the threaded recess23.

.It will be apparent from the' above that I have provided a structure inwhich the key when locked in assembled position, has no appreciablevertical movement within the key slots in thecutter shanks, orwithin thekey slot inthe spring rod, the lock member 20 serving as a means forpositively insuring a coincident vertical movement of both cutters, thekey, and the spring rod in both directions. f

This is of great importance in that by such arrangement back-lash of thecutters relative tothe key is prevented and the wear incident toy suchback-lash is eliminated.

Furtherwith the ordinarykey structure wherein the 'key slots in thecutters are of al height equal to the height of the center portion ofthe key, the key is maintained in position only bythe tension of thespring and the ends of the key bein of lesser height than said slotspermit an in ependent movement vof one or both cutters upon the key.l/Vith such ordinary construction, if one of the cutters becomes jammedin the well bore an upward pull on the underreamer will cause thekey tobecome twisted to an angled position with the corner of its medialprojection wedging against the jammed cutter, then upon a downwardmovement such corner will be forced into the key slot of such jammedcutter with the result that all the parts become locked together againstmovement.- If the parts cannot then be released by operation of the jarsof the tool' string, the `tool must be forcefully pulled from the wellwith the result that one or both of the cutters engaging the casing shoewill be broken and lost from the tool.

By preventing an independent movement A of the cutters on the key thestructure of the presentinvention `eliminates any such wedgingor-jamming of the parts.

While the form of device herein illustrated and described is welladapted for the purposes primarily stated, itis to be understood that Ido not wish to confine the invention to-thevone embodiment hereindisclosed,.for it is susceptible of embodiment in various other formsall coming Within the scope of the claims which follow.

I claim: Y 1. In an underreamer, the combination ofa body, a spring rodmounted rin the body and provided with a transverse key-receiving slot,opposed cutters having shanks provided with key-slots substantiallyaligned with the key-slot of the rod, a cutter-supporting key insertablein an inclined position through the aligned slots -when the spring rodis in a depressed position with its slot alignin with the slots of theopposed cutters, an a lock-member seated in the side of one of thecutters, having an upper edge with its surface extending longitudinallyunder, and engaging, the edge of said key for maintaining the keyagainst displacement, said lock-member being removablek to permitwithdrawal of the key, the slot of the cutter opposite the lockingmember being of greater length than the depth .of the endA of the keyengaging therein, to permit clearance in inserting the key.

2. In an underreamer, the combination of a body, a pair of oppositelydisposed cutters with slots therein, a spring-rod disposed between thecutters and carried by the body, said spring rod having a slot therein,a key received in said slots, the slot in one of said cutters being ofsuflicient vertical width to receive the adjacent end of the keyandsubstantially engage the upper and-lower edges of the key, the slot inthe other cutter 'being of considerably greater vertical width than theend of the key to permit tilting the key when inserting or withdrawingthe same, the last-named or said cutters having a removable-lockingmember for engaging the lower edge of the key to prevent the same frombeing moved downwardly at that end, the upper edge of the key at the endremote from said locking member being inclined to facilitate thedownward movement of the end of the key adjacent the locking member whenthe key is being removed.

3. In an underreamer, the combination of a body, a pair of oppositelvdisposed cutters with slots therein,a spring-rod disposed between thecutters and carried by the body, said spring rod having a slot thereinaligned with the slots in the cutters, a key having a wing at the slotof the spring-rod, the slot in one of said cutters being of suiiicientvertical width to receive one end of the key and substantially engagethe key on its upper and lower edges, the slot in the other cutter beingof considerably greater vertical width than the adjacent end of the keyto permit tilting the key when inserting or withdrawing the same, thelast-named cutter having a recess adjacent the end of the key, extendingfrom N the outer face of the cutter inwardly toward the axis of thebody, and a locking member removably mounted in said recess and engagingthe adjacent end of the key to retain the same.

4. In an underreamer, the combination of a body, a spring-rod mountedtherein and having a slot` a pair of oppositely disposed cutters carriedby the body and having slots opposite the slot in the spring rod, a keyhaving its ends received in the slots of the cutters and having a wingprojecting up' wardly on the upper edge of the key and engaging theinner sides of the cutters to prevent displacement of the key, the slotin one of said cutters being of sufficient vertical width to receive theadjacent end of the key and substantially engage the key on its upperand lower edges, the slot in the other cutter being of considerablygreater vertical width than the adjacent end of the key, so that tueslot in that cutter extends downwardly below the key to permit theladjacent end of the key to be depressed in inserting or withdrawing thekey, the last named cutter having a recess in the side thereof adjacentthe end of the key. a locking member removably mounted in said recessand engaging the ad.- jacent end of the key to retain the same, theupper edge of the key at the end thereof remote from the locking memberhaving an its middle portion and received 1nl inclined portion tofacilitate the removal of the key when the locking member has beenremoved.

5. In an underreamer, the combination of a body, a spring rod mountedtherein and having' a slot, a pair of oppositely disposed cutterscarried by the body :and having slots Opposite the Slotin the springrod, a key having vvits ends received in the slots of `the v cutters,passing through the slot of the spring rod and having a wing projectingupwardly and engaging the inner4 sides of the cutters to preventdisplacement vof the key, one of the slots of said cutters extending ithe same, operating to prevent outward` movement of the locking member.

6. In an underreamer, the combination of a body, a spring rod mountedtherein and having a slot, a pair of oppositely disposed cutters carriedby the body and having slots opposite the slot in the spring rod, a keyhaving its ends received in the slots of the cutters, passing throughthe spring rod and having a wing projecting upward y and engaging theinner sides of th'e cutters to prevent displacement of the kev, one ofthe slots of said cutters extending downwardly to permit the adjacentend of the key to be depressed to permit withdrawal of' the key from theslots, a recess in the side of the cutter adjacent that end of the key,said recess extending from the outer face 'of the cutter inwardly towardthe axis ofthe body and va locking member removably mounted in saidrecess and engaging the ad* jacent end of the key to retain the same,the lower edge of said locking member being enlarged to form a bead,said recess receiving said bead and cooperating therewith to prevent anupward movement of the locking member in in the locking member igned atTorrance, California,

day of February 1922.

RICHARD R. SMITH.

in its recess.l

this 10th Witnesses:

MARY ELLEN SMITH, J. A. ENos.

the recess, and means for retainslot of the

